We’ve seen that je suis can contract in informal language to what sounds like chu or chui. But where does that ch sound come from in chu and chui, considering there isn’t any ch sound in je suis to begin with?

To get the pronunciation chui, je suis contracts to j’suis.Je loses its vowel sound, and the resulting j’s makes the French ch sound. The same thing happens with chu, which is je suis contracted to j’su’s.

So the ch sound comes from j’s.

This is why je sais contracted informally to j’sais sounds like ché. It’s also why je sois contracted to j’sois sounds like choi. Je savais contracted to j’savais sounds like chavais. Anywhere you have the informally contracted j’s, you have the ch sound.

The de t’ part just sounds like de with a t sound on the end, followed by ça, as if it were deutt ça.

It was a woman in her 60s who said de t’ça, but it can be heard in any age group during informal conversations.

You don’t need to start saying de t’ça yourself. Just learn to recognise it. The regular de ça pronunciation works in any language situation, for example: je suis tanné de ça, or more informally: chu tanné de ça.

If you are going to use de t’ça though, keep it for informal language situations.

By the way, the woman really did say je suis, and not the informal contracted forms j’sus (chu) or j’suis (chui).